2602 Research Article Received: 11 May 2010 Revised: 14 July 2010 Accepted: 19 July 2010 Published online in Wiley Online Library: 5 August 2010 (wileyonlinelibrary.com) DOI 10.1002/jsfa.4128 Relationships between disease control, green leaf duration, grain quality and the production of alcohol from winter wheat Andrew M Watson, a* Martin C Hare, a Peter S Kettlewell, a James M Brosnan b and Reginald C Agu b Abstract BACKGROUND: Since demand for distilling wheat is expected to increase rapidly as a result of the development of the bioethanol industry, efﬁcient production will become of increasing importance. Achieving this will require an understanding of the agronomic factors that inﬂuence both grain yield and alcohol yield. Therefore ﬁve ﬁeld experiments using the winter distilling wheat variety Glasgow were conducted over three seasons (2006–2007, 2007–2008 and 2008–2009) to study the relationships between foliar disease and alcohol yield. RESULTS: There was a signiﬁcant relationship between alcohol yield and the severity of the disease septoria leaf blotch (Septoria tritici), which was present in the experiments from natural infection. Retention of green ﬂag leaf area as affected by disease control following fungicide application was also shown to be important for achieving high alcohol yields. Measurements of grain quality showed that high thousand-grain weight and low grain protein concentration were signiﬁcantly related to increased alcohol yield. CONCLUSION: The experiments showed the importance of disease management to protect alcohol yields in the distilling wheat crop. Fungicides that provide greater disease control and improved green leaf retention are likely to be beneﬁcial to alcohol yield. c  2010 Society of Chemical Industry Keywords: grain quality; alcohol; bioethanol; wheat; disease; green leaf duration; fungicide INTRODUCTION Traditionally, distilling wheat in the UK has been grown for the Scotch whisky industry. This market requires an annual production of 7 × 10 5 t of wheat to produce approximately 3 × 10 8 L of alcohol (LA) each year. 1 There is growing interest in the production of distilling wheat for the emerging fuel alcohol market. Fuel alcohol, commonly known as bioethanol, is produced using similar techniques to those used by the potable alcohol industry. Growing interest in biofuels has led to concerns over the production of large areas of non-food crops threatening the availability and affordability of food. 2 There have also been concerns over the amount of CO 2 emitted during production and processing of the fuel. 3 If biofuels are to be produced, it is important to address these concerns by maximising efﬁciency both in the ﬁeld and during processing. Achieving a high level of alcohol production per hectare will help minimise the cultivated area of non-food crops, easing pressures on both food production and the environment. Maximising the efﬁciency of crop production can also help limit the amount of CO 2 emitted during production. Achieving a high grain alcohol yield (LA t −1 ) will also help maximise processing efﬁciency and reduce energy requirements. To achieve these objectives, it is necessary to have a thorough understanding of the agronomic factors that inﬂuence alcohol production. Previous investigations have studied relationships between disease control, green ﬂag leaf area duration and grain quality, 4,5 but none has looked at the inﬂuence of these factors on alcohol yield. This study is therefore designed to expand on what is known to determine how these factors inﬂuence the production of alcohol. MATERIALS AND METHODS Experimental design Five ﬁeld experiments were conducted in Shropshire, UK at Harper Adams University College. During the study, experiment 1 was established for the 2006–2007 growing season, experiments 2 and 3 were conducted in the 2007–2008 growing season and experiments 4 and 5 were conducted in the 2008–2009 growing season. Each experiment used the soft winter wheat variety Glasgow recommended for distilling. All experiments were conducted using a randomised block design with seven replicates. ∗ Correspondence to: Andrew M Watson, Crop and Environment Research Centre, Harper Adams University College, Newport, Shropshire TF10 8NB, UK. E-mail: awatson@harper-adams.ac.uk a Crop and Environment Research Centre, Harper Adams University College, Newport, Shropshire TF10 8NB, UK b Scotch Whisky Research Institute (SWRI), Riccarton, Edinburgh EH14 4AP, UK J Sci Food Agric 2010; 90: 2602–2607 www.soci.org c  2010 Society of Chemical Industry